In recent years, as described in Evolution and Proliferation of Surveillance Cameras and ‘Inconvenience’—Introduction of Electronic Eyes on Rise to Cope with High Incidence of Crimes (Non-patent document 1), there has been a growing tendency toward installing surveillance cameras in stores and over streets for security purposes. With an increasing number of such networks being put in use, so-called web cameras have been installed here and there, with the result that it has been increasingly easy to monitor an image of an area of business facility remotely. As described in JP-A No. 84529/2002 (patent document 1) and JP-A No. 234653/1999 (patent document 2), a system for distributing an image that has been inputted with the use of a surveillance camera via a network has been introduced. If an image inputted with the use of a surveillance camera installed in a shop can be distributed to general households, the image can enable consumers to check the availability of merchandise of their interest, possibly causing the consumers to visit the shop and do some shopping. However, there may be cases in which distributing an image showing customers visiting a shop via a network that is accessible by the general public is not desirable in the light of personal rights and privacy of the persons being viewed. In such an application of a surveillance camera, there is also another problem in that an image inputted in a shop may not necessarily show all available merchandise, since customers visiting the shop may block the view of the surveillance camera.    [Patent document 1] JP-A No. 84529/2002    [Patent document 2] JP-A No. 234653/1999    [Non-patent document 1] S. Segawa, “Evolution and Proliferation of Surveillance Cameras and ‘Inconvenience’ m Introduction of Electronic Eyes on Rise to Cope With High Incidence of Crimes”, [online], (Aera magazine: Aug. 4, 2003 issue), the home page of the Asahi Shimbun, [searched on Feb. 9, 2004], www.asahi.com/housing/zasshi/TKy200308200179.html [Non-patent document 2] Takeshi Naemura, Hiroshi Harashima: “Thermo-key: Human Region Segmentation from Video Using Thermal Information”, Symposium on Real World Information Systems, program collection, pp. 29-32 (2003.09).